{"id":"CVE-2026-23920","state":"PUBLISHED","title":"Host and event action script regex validation can be bypassed in certain situations, leading to potential command injection","description":"Host and event action script input is validated with a regex (set by the administrator), but the validation runs in multiline mode. If ^ and $ anchors are used in user input validation, an injected newline lets authenticated users bypass the check and inject shell commands.","publishedAt":"2026-03-24T18:27:52.882Z","updatedAt":"2026-03-26T03:55:29.372Z","severity":{"score":7.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","source":"Zabbix"},"assigner":"Zabbix","products":["Zabbix Zabbix"],"affected":[{"vendor":"Zabbix","product":"Zabbix","defaultStatus":"unknown","versions":[{"version":"7.0.0","status":"affected","lessThanOrEqual":"7.0.21","changes":[{"at":"7.0.22","status":"unaffected"}],"versionType":"git"},{"version":"7.2.0","status":"affected","lessThanOrEqual":"7.2.14","changes":[{"at":"7.2.15","status":"unaffected"}],"versionType":"git"},{"version":"7.4.0","status":"affected","lessThanOrEqual":"7.4.5","changes":[{"at":"7.4.6","status":"unaffected"}],"versionType":"git"}],"repo":"https://git.zabbix.com/","modules":["Server","Proxy"]}],"references":["https://support.zabbix.com/browse/ZBX-27639"],"weaknesses":["CWE-78"],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/23xxx/CVE-2026-23920.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23920","state":"PUBLISHED","datePublished":"2026-03-24T18:27:52.882Z","dateUpdated":"2026-03-26T03:55:29.372Z","assignerShortName":"Zabbix","assignerOrgId":"72de3e22-0555-4a0d-ae81-9249e0f0a1e8","dateReserved":"2026-01-19T14:02:54.327Z"},"containers":{"cna":{"title":"Host and event action script regex validation can be bypassed in certain situations, leading to potential command injection","descriptions":[{"lang":"en","value":"Host and event action script input is validated with a regex (set by the administrator), but the validation runs in multiline mode. If ^ and $ anchors are used in user input validation, an injected newline lets authenticated users bypass the check and inject shell commands."}],"affected":[{"vendor":"Zabbix","product":"Zabbix","defaultStatus":"unknown","versions":[{"version":"7.0.0","status":"affected","lessThanOrEqual":"7.0.21","changes":[{"at":"7.0.22","status":"unaffected"}],"versionType":"git"},{"version":"7.2.0","status":"affected","lessThanOrEqual":"7.2.14","changes":[{"at":"7.2.15","status":"unaffected"}],"versionType":"git"},{"version":"7.4.0","status":"affected","lessThanOrEqual":"7.4.5","changes":[{"at":"7.4.6","status":"unaffected"}],"versionType":"git"}],"repo":"https://git.zabbix.com/","modules":["Server","Proxy"]}],"references":[{"url":"https://support.zabbix.com/browse/ZBX-27639"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":7.7,"vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-78","lang":"en","description":"CWE-78 CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')","type":"CWE"}]}],"providerMetadata":{"shortName":"Zabbix","orgId":"72de3e22-0555-4a0d-ae81-9249e0f0a1e8","dateUpdated":"2026-03-24T18:27:52.882Z"},"impacts":[{"capecId":"CAPEC-88","descriptions":[{"lang":"en","value":"CAPEC-88: OS Command Injection"}]}],"configurations":[{"lang":"en","value":"Authenticated users with script execution permissions can bypass ^ and $ regex validation by injecting a newline character.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>Authenticated users with script execution permissions can bypass ^ and $ regex validation by injecting a newline character.</p>"}]}],"workarounds":[{"lang":"en","value":"It is possible to use \\A and \\z anchors in the regex validation as a workaround.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>It is possible to use \\A and \\z anchors in the regex validation as a workaround.</p>"}]}],"solutions":[{"lang":"en","value":"Update the affected components to their respective fixed versions.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>Update the affected components to their respective fixed versions.</p>"}]}],"credits":[{"lang":"en","value":"Zabbix wants to thank YoKo Kho (@YoKoAcc) from PT ITSEC Asia, Tbk for submitting this report on the HackerOne bug bounty platform.","type":"reporter"}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"Vulnogram 1.0.1"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-25T00:00:00+00:00","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3","id":"CVE-2026-23920"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-03-26T03:55:29.372Z"}}]}}}